Resolves and caches Domain Name System (DNS) names for this computer. If this service is stopped, this computer will not be able to resolve DNS names and locate Active Directory domain controllers. If this service is disabled, any services that explicitly depend on it will fail to start.

The DNS client service is used in looking up and caching DNS entries for use in the future. This updates the revolver cache which it uses to fetch the identity of a DNS entry. A DNS (domain naming system) is a name applied to a particular website IP address. Using this service will in theory increase the speed of DNS lookups as it will search the local DNS revolver cache before it attempts to ask a network DNS server. This service though is not required and can safely be disabled if you do not wish to use it for whatever reason. The server can also be set to manual but may activate when required.

It may be useful to know the DNS revolver cache can be viewed with the 'IPCONFIG /displaydns' console command and can also be cleared with the 'IPCONFIG /flushdns' console command. In order to view the revolver cache or to clear it you will need to be running the service.